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Radiation Protection Competency 1.7

DRAFT Study Guide RP 1.7-1 Radiation ProtectionRevision 1 August 1997

Competency 1.7 Radiation protection personnel shall demonstrate a working level knowledge ofAs-Low-As-Reasonably-Achievable (ALARA) principles, and their applicationto radiological work activities.

1. SUPPORTING KNOWLEDGE AND/OR SKILLS

a. Describe the various components of an effective ALARA program including operations, engineering, andmanagement controls.

b. Describe how optimization techniques, including cost-benefit analysis, are used in the ALARA process.c. Discuss the essential elements of the job planning process and the post job ALARA review for work

performed in a radiation or radioactive contamination area.d. Describe the various radiological performance indicators that are applicable to the ALARA process.e. Calculate person-rem estimates and use the results in ALARA cost-benefit analysis.f. Discuss methods to minimize total effective dose equivalent (TEDE) by evaluating the trade-offs in

considering the internal and external dose components.g. Using knowledge of ALARA principles, discuss how to perform an evaluation of a radiation job plan and

the associated worker job performance.



2. SUMMARY

Introduction to ALARA

ALARA means As Low As is Reasonably Achievable, which is the approach in radiation protectionto manage and control exposures (both individual and collective) to the workforce and to the generalpublic to as low as is reasonable, taking into account social, technical, economic, practical, and publicpolicy considerations. ALARA is not a dose limit, but a process which has the objective of attainingdoses as far below the applicable limits as is reasonably achievable.

Fundamental ALARA techniques include minimizing time in radiological areas, maximizing distancefrom radiation sources, providing adequate shielding from all radiation, providing for decontaminationof personnel and equipment, and controlling ingestion and inhalation of radionuclides for all workers.Personnel responsible for ALARA should review work packages and facility design, provideawareness training for personnel, and set personnel exposure goals.

Two basic conditions are considered necessary in any program for keeping occupational exposuresas far below the specified limits as is reasonably achievable. The management of the facility shouldbe committed to maintaining exposures as low as reasonably achievable, and the personnel responsiblefor radiation protection should be continually vigilant for means to reduce exposures. The control of occupational exposures is required to be implemented through facility design andengineering controls; together with procedural controls, such as work area monitoring and posting;control of work-area access; and individual monitoring and dose assessment. Collectively, thesecontrols provide assurance that exposures are maintained ALARA.

Planning of radiological work is essential. The purpose of planning is to ensure all factors that mayinfluence the adequate and efficient performance of a task, are recognized and that appropriate skills,training, and resources are available. The radiation work permit (RWP) is a radiation controlprocedure and essentially documents the planning process. The permit lists the radiation controls,requirements, and restrictions for work in a radiological area. Other important elements in theplanning process are training personnel, scheduling work, briefing and debriefing workers, anddocumenting and analyzing historical data and work experiences. Upon completion of a task, adebriefing of those performing the work may be valuable in identifying problems encountered,techniques for improving the future performance of similar tasks, and techniques for further reducingexposures.



ALARA Program Components

The 10 CFR 835 implementation guide (IG), Occupational ALARA Program lists the essentialelements that shall be incorporated into an acceptable occupational ALARA program:

1. Management commitment2. Assignment of responsibility3. Administrative control levels4. Radiological performance goals5. ALARA training6. Plans and procedures7. Internal audits/assessments8. Optimization methodology9. Radiological design review10. Radiological work/experiment planning11. Records

For the basis of this discussion, the basic components of an ALARA program to reduce dose include:

Designing operation controls to reduce doseDesigning engineering controls to reduce doseRequiring management to help design, commit to, and manage an ALARA programMinimizing time in radiologically controlled areasMaximizing the distance from a source of radiationUsing shielding whenever possible

Operation Controls

One part of an ALARA program is to make sure the basic controls are operating at their best. Toachieve this, inspection tours to check on access, mirrors, and visibility should be performed. Inservice inspections check the use of remote control equipment, TV, snap on insulation, platforms, etc.Other items to check include:

Remote readout instrumentation,Remote valve/equipment operatorsSampling stations, piping, valving, hoods, sinks



Administrative Controls

During operations, engineered controls are probably the most effective means of controlling exposure,if included in the design and construction of a facility. However, administrative controls, such asoperational procedures, are designed to provide guidance, direction, and limitations for operationalactivities. Each step in a procedure should be thought through, and its impact on exposure evaluated.For example, shielding, remote operation, distance, specialized tools, protective equipment,manpower requirements, exposure rates, exposure times, and alternative procedures should all becarefully considered.

DOE sites must establish a challenging level of administrative control which is more restrictive thanthe DOE Radiological Control Manual administrative control level of 2 rem/yr. As stated in the for10 CFR 835 IG, Occupational ALARA Program:

"These administrative controls should be established at challenging levels, well below the controllinglimit, taking into consideration the exposure history of the facility and the aggressiveness of thefacility's exposure controls (Radiological Control Manual, Section 211). Administrative exposurecontrols may require increasing degrees of review, intervention and management approval before theyare exceeded, depending on how close the expected dose is to the DOE occupational exposure limit.Proper implementation of the administrative control levels should prevent personnel from exceedingthe DOE limits, and also aid in attaining and maintaining occupational exposures ALARA."

Workplace Monitoring

Workplace monitoring provides a control mechanism to detect and quantify external radiation levels,enables measures to be taken to prevent unanticipated and unplanned exposures, and contributes tomaintaining actual exposures ALARA.

10 CFR 835, Occupational Radiation Protection, requires:

Implementation of ALARA techniques to ensure that occupational exposures are maintained atALARA levels. Measurements of radioactivity concentrations in workplace air be performed. Periodic air sampling must be performed in areas where employees are likely to exceed twopercent, or more, of the annual limitation on intake (ALI) values. Continuous, real-time monitoring must be performed in areas where an individual could beexposed to airborne radioactivity concentrations exceeding the derived air concentration (DAC)values set forth in Appendix A to 10 CFR 835.



Real-time monitors must have an alarm capability and have sufficient sensitivity to alert potentiallyexposed individuals that their immediate action is necessary to minimize or terminate an inhalationexposure. Bioassay measurements (measurements of radioactive material within and excreted from thebody) must determine the magnitude of internal doses and include directions regarding whichemployees should be included in bioassay programs. These measurements also confirm theeffectiveness of the confinement and air monitoring systems.

Dosimeters should be appropriate for the kinds, energies, and intensities of radiation fields. Thelocation where the dosimeter is worn on the body should be consistent and documented. The lens ofthe eye and the skin frequently require special consideration. Radiation surveys in the field providea basis for making ALARA decisions in the field.

Engineering Controls

There are several engineering factors to consider when designing a facility. They include:

The discharge of radioactive liquid to the environmentControl of contaminationEfficiency of maintenanceEase of decontamination and operationsSelecting components to minimize the buildup of radioactivityProviding support facilities for donning and removing protective clothing and for personnelmonitoringShielding requirementsErgonomics consideration Access control designed for hazard levelSurfaces that can be decontaminated or removedEquipment that can be decontaminated

The primary means for maintaining exposure ALARA should be through physical controls such asconfinement, ventilation, remote handling, and shielding. Some of the factors that should be takeninto consideration when designing new facilities or modifying existing ones are:

Traffic patternsRadiation zoningChange room location and sizeAdequacy of personnel decontamination facilities



Location of fixed survey equipmentIn addition, locations for the temporary storage of radioactive wastes must be designed into both thebuilding plan and the plan for each laboratory room or radiation area.

Management Controls

Management should design and implement an ALARA program; provide resources such as tools,equipment, and adequate personnel; create and support an ALARA review committee; approveALARA goals; and design and implement worker training.

Management commitment to minimizing radiation exposures is effected through the followingaspects:

Facility personnel should be made aware of management's commitment to keep occupationalexposures ALARA.Management should: periodically perform a formal audit to determine how exposures might belowered.Ensure that there is a well-supervised radiation protection capability with well-definedresponsibilities.Ensure that facility workers receive sufficient training in radiation protectionThe Radiological Control Manager should be given sufficient authority to enforce safe facilityoperation.Modifications to operating and maintenance procedures and to equipment and facilities shouldbe made where they will substantially reduce exposures at a reasonable cost.

An ALARA committee should be established at each facility. The membership should includemanagers and workers from the line, the technical support organization and the radiological controlorganization. It is more effective if a line manager, such as the director of operations, research, ormaintenance serves as the chair. This committee may be part of a general safety or radiation safetycommittee whose functions include ALARA activities, and may possibly be combined with theradiological awareness committee (see Article 132 of the Radiological Control Manual) for smallerfacilities.

The ALARA committee should make recommendations to management to improve progress towardminimizing radiation exposure and radiological releases. The committee should evaluate items suchas construction and design of facilities and systems, planned major modifications or work activities,



as well as experimental test plans for exposure, waste and release minimization. The ALARAcommittee should also receive, as a minimum, the results of all reviews and audits, both internal andexternal, and should review the overall conduct of the radiological control program.

The primary control of radiation exposures remains with the individual and with the individual’simmediate supervisors. In many facilities, a major part of radiation exposure is received duringmaintenance, handling of radioactive wastes, in-service inspection, refueling, and repairs.

Time

The control of exposure time (time spent in a radiation field) is the first major health physics principleavailable to an occupational worker to limit his/her exposure to an external radiation source. It isimportant to realize that the radiation dose received by the worker is directly proportional to the timespent in a radiation field. Therefore, to minimize the dose received, reduce the time spent in theradiation field. Work processes and special tooling can help reduce time in a radioactive work area.The control of exposure time is a significant factor in the issuance of RWPs at DOE facilities.

Plan and discuss the task prior to entering the area. Use only the number of workers actuallyrequired to do the job.Have all necessary tools present before entering the area.Use mock-ups and practice runs that duplicate work conditions.Take the most direct route to the job site, if possible and practical.Never loiter in an area controlled for radiological purposes.Work efficiently and swiftly.Do the job right the first time.Perform as much work outside the area as possible or, when practical, remove parts orcomponents to areas with lower dose rates to perform work.In some cases, the radiological control personnel may limit the amount of time a worker may stayin an area due to various reasons. This is known as "stay time". If you have been assigned a staytime, do not exceed this time.

Distance

A very common and extremely effective technique to reduce personnel exposure is to increase thedistance between the worker and the radiation source. In many instances, this approach is moreimportant than controlling exposure time and can be easily demonstrated for "point" (small) sourcesof radiation. While the exposure-time relationship follows a direct dependence, (i.e., reducing thetime spent in a radiation field by one-half reduces the exposure to the worker by one-half) distancedependence often follows the "inverse-square" (second power) law. Thus, doubling the distance froma point source reduces the exposure to the worker by a factor of four! It should be noted that

Dose RateA Dose RateB

Distance 2B

Distance 2A



situations do exist where the inverse square law does not apply. In these cases, the relationshipbetween the dose received and the distance from the source does not always follow a simple rule.

Methods for maximizing distance from sources of radiation

The worker should stay as far away from the source of radiation as possible.

For point sources, such as valves and hot spots, the dose rate follows a principle called the inversesquare law:

This law states that if you double the distance, the dose rate falls to 1/4 the original dose rate. If youtriple the distance, the dose rate falls to 1/9 the original dose rate.

Be familiar with radiological conditions in the area.

During work delays, move to lower dose rate areas.

Use remote handling devices when possible.

Shielding

Shielding the source of radiation becomes important when minimizing time and maximizing distanceare not sufficient to reduce personnel exposures to acceptable levels. Determining the requiredshielding is influenced strongly by the type (alpha, beta, gamma, x-ray, neutron) and the energy of theradiation. Shielding is one of the basic tenets of ALARA. 10 CFR 835, Subpart K states that theshielding design objective for facilities should be 0.5 mrem/hr for areas of continuous occupancy(2,000 hrs/yr) or as far below this as possible. Material selection for shielding should includeoperations, maintenance, decontamination, and decommissioning.

Shielding reduces the amount of radiation dose to the worker. Different materials shield a workerfrom the different types of radiation.

Take advantage of permanent shielding including nonradiological equipment/structures.

Use shielded containments when available.

Wear safety glasses/goggles to protect your eyes from beta radiation, when applicable.

Temporary shielding (e.g., lead or concrete blocks) can only be installed when proper procedures are



used. Temporary shielding will be marked or labeled with wording such as, "Temporary Shielding -Do Not Remove Without Permission from Radiological Control." Once temporary shielding isinstalled, it cannot be removed without proper authorization.

It should be remembered that the placement of shielding may actually increase the total dose (e.g.,person-hours involved in installing and removing shielding).

Other ALARA Program Components

Area Arrangement

Maintenance Needs

Radiological Control Needs

Optimization of ALARA

The optimization process in ALARA refers to the process of achieving balance between radiationprotection or reduction of risk, cost, and benefit. Radiation doses are ALARA only when thesefactors are in balance. If an imbalance exists, either the risk is too high, or the cost is too high for theidentified benefit. The optimization process should be used whenever decisions regarding theimplementation of a radiation protection practice will be costly, complex, and/or involve significantdose savings, (for example, facility design and engineering controls). The major method ofoptimization is cost-benefit analysis, which is described in detail in ICRP 37, Cost-Benefit Analysisin the Optimization of Radiation Protection.

Cost-Benefit Analysis

The suggested approach to performing a cost-benefit analysis includes these steps:

Identify all possible options, including the "do nothing" option.

Determine the individual and collective dose equivalents for each option.

Identify all costs and determine the net costs for each option.

Determine the cost equivalent of the doses resulting from each option.

Sum the costs to determine the total net cost for each option.

The option with the lowest total net cost is the optimal option.

Pre and Post ALARA Reviews



Technical requirements for the conduct of work, including construction, modifications, operations,maintenance, and decommissioning, should incorporate radiological criteria to ensure safety andmaintain radiation exposures ALARA. The primary methods used to maintain exposures ALARAare facility and equipment design features, augmented by administrative and procedural requirements.To accomplish this, the design and planning processes should incorporate radiological considerationsin the early planning stages.

Essential Elements of Preliminary Job Planning

Preliminary Planning and Scheduling

Plan in advance

Delete unnecessary work

Determine expected radiation levels

Estimate collective dose

Sequence jobs

Schedule work

Select a trained and experienced workforce

Identify and coordinate resource requirements

Prepare Technical Work Documents

Include special radiological control requirements in technical work documents

Perform ALARA prejob review

Plan access to, and exit from, the work area

Provide for service lines (air, welding, ventilation)

Provide communication (sometimes includes closed-circuit television)

Remove or shield sources of radiation

Plan for installation of temporary shielding

Decontaminate

Work in lowest radiation levels

Perform as much work as practicable outside radiation areas

State requirements for standard tools

Consider special tools, including robots



State staging requirements for materials, parts, and tools

Incorporate radiological control hold points

Minimize discomfort of workers

Revise estimates of person-rem

Prepare radiological work permits (RWPs)

The RWP should be issued to control work activities in radiological areas, and shall be approved bythe supervisor(s) in the radiation protection organization and in the organization responsible for thework before it is begun (Radiological Control Manual, Section 323.4). For ALARA purposes, apreliminary estimate of time and radiation dose for the activity and any special ALARA controlsshould be provided, as appropriate (10 CFR 835 IG, Occupational ALARA Program). Specificcriteria for the use of RWPs is outlined in the Radiological Control Manual, Section 322.

Prepare Temporary Shielding

Design shielding to include stress considerations

Control installation and removal by written procedure

Inspect after installation

Conduct periodic radiation surveys

Prevent damage caused by heavy lead temporary shielding

Balance radiation exposure received in installation against exposure saved by installation

Shield travel routes

Shield components with abnormally high radiation levels early in the maintenance period

Shield position occupied by worker

Perform directional surveys to improve design of shielding by locating source of radiation

Use mock-ups to plan temporary shielding design and installation

Consider use of water-filled shielding



Rehearse and Brief

RehearseUse mock-ups duplicating working conditionsUse photographs and videotapes Supervisors conduct briefings of workers

Perform Prejob ALARA Reviews

A prejob ALARA review should be conducted for non routine or complex radiological workactivities. Specific requirements for the conduct of a prejob ALARA review should be included inthe site-specific contractor radiological control program. A prejob ALARA review is indicated whenany of the following trigger levels may be met during the work evolution:

Estimated individual or collective dose greater than preestablished valuesPredicted airborne radioactivity concentrations in excess of preestablished valuesWork area where removable contamination is greater than 100 times contamination area postinglimitsEntry into areas where dose rates exceed one rem/hourPotential radioactive releases to the environment

Radiological requirements identified as part of the prejob ALARA review should be documented inthe job plans, procedures or work packages. The prejob ALARA review should consider thefollowing points, at a minimum:

Inclusion of radiological control hold points in the technical work documentsElimination, or reduction, of radioactivity through line flushing and decontaminationUse of work processes and special tooling to reduce time in the work areaUse of engineered controls to minimize the spread of contamination and generation of airborneradioactivitySpecification of special radiological training or monitoring requirementsUse of mock-ups for high-exposure or complex tasksEngineering, design and use of temporary shielding to reduce radiation levelsWalkdown or dry-run of the activity using applicable proceduresStaging and preparation of necessary materials and special toolsMaximization of prefabrication and shop workReview of abnormal and emergency procedures and plans



Identification of points where signatures and second party or independent verifications arerequiredEstablishment of success or completion criteria, with contingency plans to anticipate difficultiesDevelopment of a prejob estimate of collective dose to be incurred for the jobProvisions for waste minimization and disposal

Perform Prejob briefings

Any work evolution requiring a prejob ALARA review should also include a prejob briefing to beheld prior to the conduct of work. Specific requirements for the conduct of a prejob briefing shouldbe included in the site-specific contractor radiological control program. Prejob briefings should beconducted by the cognizant work supervisor and should include, at a minimum, the following details:

Scope of work to be performed

Radiological conditions of the workplace

Procedural and RWP requirements

Special radiological control requirements

Radiologically limiting conditions, such as contamination or radiation levels that may void theRWPRadiological control hold points

Communications and coordination with other facility work groups

Provisions for housekeeping and final cleanup

Emergency response provisions

Essential Elements of Post Job Reviews

Post-job ALARA reviews should be held, following conduct of radiological work, according to thesite-specific contractor radiological control program. Typical criteria for work evolutions which willrequire a postjob ALARA review are:

Any job requiring a prejob ALARA reviewThe actual collective dose exceeding the estimated collective dose by at least 25%The work evolution was nonroutine

A postjob briefing gives the radiological control technician and the workers the opportunity tocritique the work performance. During the critique, information is gathered as soon as possible afterthe job is completed while it is still fresh in everyone's mind. The information gathered at the postjobbriefing may include discussions of what went wrong, what could have been done differently to



reduce exposures, and what went right. The postjob briefings rely heavily on the input of eachworker for information on how to best reduce exposure the next time that job is performed. Typicalquestions asked at a postjob briefing are:

1. Were there any problems performing the job in accordance with the procedure?2. Did you have the tools and equipment needed to perform the work? Would special tools ease

the job?3. Were there any unexpected conditions noted during the work? Could these conditions have

been anticipated?4. Were there any unexpected delays in the performance of the job? What was the cause of the

delay?5. Was temporary shielding used? Could the use of temporary shielding reduce exposures

received for this job?Do not limit yourself to just these questions. The brief should be a dynamic exchange of informationbetween all parties.

Postjob ALARA Reviews

Information gathered from the postjob briefing will then be evaluated by ALARA engineers. Apostjob ALARA review is a formal document that evaluates what went right, as well as, what wentwrong, determining root causes and instituting corrective measures. This documentation will thenbe filed for future use, enabling ALARA engineering to write a prejob ALARA review incorporatingcorrective measures from lessons learned. The postjob ALARA review is a formal preservation oflessons learned information and is important to ascend the learning curve and help maintain ALARA.

ALARA Performance Indicators

DOE-STD-1048-92, DOE Performance Indicators Guidance Document, gives specific guidance onthe use of performance indicators in the ALARA program assessment process.

Goals for individual and collective doses should be established and actual doses received should betracked to improve the performance of nonroutine and high-exposure radiological tasks. Linemanagement should document the goals, their status, and the facility's performance. At least annually,a formal summary of performance related to efforts in dose reduction and contaminationminimization, and in achievement of the site's or facility's radiological goals should be given to seniormanagement in an ALARA report. This information can then be used to feed back into the prejoband postjob briefings.

The radiological performance indicators listed below are suggested by the Radiological Control



Manual as tools to assist facility management in focusing priorities to establish excellence inradiological control. Table 1, following, provides indicators that can be used to conduct a moredetailed analysis of radiological performance.

Collective Dose (person-rem): This goal should be based upon planned activities and historicalperformance. For those sites that have neutron radiation, a goal for collective neutron doseshould also be established.Skin and Personal Clothing Contamination Occurrences (number): Personnel contaminations mayindicate a breakdown of controls intended to prevent the spread of contamination. Intakes of Radioactive Material (number): Personnel intakes of radioactive material should beminimized and management should focus attention on any failure of the controls that results inintakes.Contaminated Area Within Buildings (square feet): Operating with a smaller contaminated arearesults in less radioactive waste, fewer personnel contaminations, and improved productivity. Thereduction of existing contaminated areas needs to be balanced by the recognition that thisgenerates radioactive waste. Goals for both should be correlated.Radioactive Waste (cubic feet): Minimizing the generation of radioactive waste reduces theenvironmental impact of DOE operations, helps reduce personnel exposure, and reduces costsassociated with handling, packaging, and disposal.Liquid and Airborne Radioactivity Released (curies): Minimizing effluents reduces theenvironmental impact of DOE operations and reduces the costs associated with remediation.



Table 1 Suggested Radiological Performance Indicators

Exposure control

A. Collective dose in person-rem

B. Average worker dose in rem

C. Maximum dose to a worker in rem

D. Number of unplanned exposures resulting in doses greater than the administrative control level

E. Number of dose assessments for lost or damaged dosimeters

F. Maximum neutron dose to a worker in rem

Personnel Contamination

A. Number of skin and personal clothing contaminations

B. Number of contaminated wounds

C. Number of facial contaminations

Control of Internal Exposure

A. Number of new confirmed depositions

B. Number of airborne events

C. Number of alarms on airborne monitors (actual and false)

D. Number of airborne radioactivity areas

E. Area of airborne radioactivity areas in square feet

Control of Contaminated Areas in Operational Areas

A. Number of contamination and high contamination areas

B. Area of contamination areas in square feet

C. Area of high-contamination areas in square feet

D. Number of spills

Minimization of Radioactive Waste

A. Volume and activity of radioactive waste in cubic feet and curies, respectively

B. Number of cubic feet not subject to volume reduction by incineration, compaction, or other means

Control of Radioactive Discharges

A. Activity of liquid-radioactivity discharges in curies

B. Activity of airborne-radioactivity discharges in curies



Problem

A ventilation system would lower the average annual TEDE at a radioactivegas-handling facility by 1.5 rem. Fifteen workers work regularly at thefacility. What annualized cost, over the life of the ventilation system, wouldjustify the addition of the system?

Solution

Calculate the collective annual person-rem saved by multiplying the averageannual dose saved by the number of workers:

1.5 rem x 15 persons = 22.5 person-rem

Since DOE policy dictates a value of $1,000 per person-rem saved, calculate thejustifiable annualized cost of the ventilation system by multiplying the person-remdollar value by the collective person-rem saved:

$1,000/person-rem x 22.5 person-rem = $22,500

Therefore, if the ventilation system can be added for an annualized cost of lessthan $22,500, the system should be implemented. Remember, annualized costmeans the total cost divided by the remaining operating life of the facility.

Cost-Benefit Analysis

The use of cost-benefit analysis in the ALARA process involves assigning a dollar value to a person-rem and comparing that against the cost of implementing a particular exposure-reduction technique.Such techniques include system and facility design modifications, addition of engineering controls,and modifications to administrative controls. If the cost of the change is less than the dollar value ofperson-rem saved by the change, the change is cost effective and should be implemented. ICRP 37,Cost-Benefit Analysis in the Optimization of Radiation Protection, gives specific guidance on thecalculational methods used to arrive at a dollar value for a person-rem. PNL-6577, Department ofEnergy Health Physics Manual of Good Practices for Reducing Radiation Exposure to Levels thatare As Low As Reasonably Achievable (ALARA), uses $1,000 per person/rem in all examples andcalculations.

Person-Rem Calculations

IDEALIZED ALARA FUNCTION

COST OF INCURRING AN INCREMENT OF DOSE

Incr

easi

ng C

ost i

n D

olla

rs

Decreasing Dose Level



ALARA Cost-benefit analysis

The International Commission on Radiological Protection (ICRP) has attempted to further analyzethe "...economic and social factors" in ICRP 55. The DOE and the Nuclear Regulatory Commission(NRC) have also addressed this issue in various publications and regulatory guides. The objectiveis to optimize dose reduction activities, (i.e., to determine at what point additional expenditures willnot result in cost effective dose savings). To put it another way, at what point would the moneyspent on dose reduction be better spent reducing other hazards which may pose greater risks? Howmuch, in dollars, is a rem worth?

Using the BEIR V Report, Health Effects of Exposure to Low Levels of Ionizing Radiation, 1990,estimates on risk, values of $2,000 to $10,000 per rem have been suggested.

The values to be used depend on other factors, including:Perception or acceptance of the riskWho benefits and who is at riskIndividual dose distributions (e.g., a percent of some limit)Time distribution of doses (e.g., "tails" of rad waste burial dose curves)The probability that the dose will actually be received (such as in design considerations), Additional factors including population age distributions and occupational vs. generalpopulation doses

Cost-benefit can be shown graphically:

Minimizing TEDE Dose

100mrem/hr x 0.202.5mrem/DAC hr

8DAC


Derived air concentration (DAC): For the radionuclides listed in Appendix A of 10 CFR 835, the airborne concentration that equals1

the ALI divided by the volume of air breathed by an average worker for a working year of 2,000 hours (assuming a breathing volume of 2,400m). 3

For radionuclides listed in Appendix C of 10 CFR 835, the air immersion DACs were calculated for a continuous, nonshielded exposure viaimmersion in a semi-infinite atmospheric cloud. The values are based upon the DAC found in Table 1 of the U. S. Environmental Protection Agency'sFederal Guidance Report No. 11, Limiting Values of Radionuclide Intake and Air Concentration and Dose Conversion Factors for Inhalation,Submersion, and Ingestion , September 1988.


In past years, the common practice at nuclear facilities has been to always wear a respirator if thereis airborne radiation present at the work site. However, when analyzed in terms of ALARA, thispractice may not be the best solution for a particular job. In order to minimize the total effective doseequivalent (TEDE), radiation protection personnel must analyze the internal (airborne) dose andcompare it to the external dose.

The use of respirators must be analyzed carefully at the start of each job, because there are a numberof negative effects to the wearer. The use of respirators causes impairment of communication, addedstress, reduced workmanship, and increased time in the radioactive area (when wearing a respirator,assume a 20% increase in work time). If the external dose received due to the increased work timeis higher then the internal dose saved, than it would be ALARA not to wear a respirator in order tolimit the time spent in the radiation field.

The equation shown can be used to below determine the incremental external dose incurred due tothe increase in work time (assuming 20%) by using a respirator, and comparing it to the internal doserate of 2.5 mrem per DAC hour .1

Example

Assume the external dose rate is 100 mrem/hr and respirators increase work time by 20%. At whatairborne concentration, in DAC, are respirators ALARA?



3. SELF-STUDY SCENARIOS/ACTIVITIES AND SOLUTIONS

Exercise 1

Following a major repair of some contaminated equipment, the work area needs to be picked up. Thework area is about 30 feet by 30 feet square. The initial plan calls for a worker to go into thecontamination area to pick up debris. The debris consists mainly of absorbent paper, plastic, tools,and broken parts. The debris is to be sorted and disposed of in two radioactive waste containerslocated in the contaminated area. The ambient dose equivalent rate in the area is about 10 mrem/hr,with two marked areas of contamination where the dose equivalent rates are on the order of 50mrem/hr (at 1 meter). The dose equivalent rates are attributable to gamma rays, and no airborneactivity is present. In the corner of the work area is a small area that is roped off and properly labeledas a high-radiation area. It is anticipated that it will take a worker in full protective clothing 30minutes to do the job.

Briefly list important ALARA elements in the performance of this job that would begin to providethe basis for the RWP, and subsequent briefing of the worker. Estimate the dose equivalent to thisworker for this job.

Your Solution:



Exercise 2

The worker was briefed on the objective of the job and the items on the RWP. The worker enteredthe area, and began to pick up debris. After a while he noticed that the radioactive waste containerswere located right next to one of the spots with the highest contamination. He immediately dismissedthis thought and decided to keep doing the task at hand. Upon being notified that the 30 minutes hadelapsed, the worker removed the protective clothing, was frisked for contamination, and left the area.The worker's dosimeter read 10 mrem. A debriefing was held after the job was completed.

Briefly list some items that should be covered in the debriefing. Evaluate the worker's performance.

Your Solution:



Exercise 3

Some vacuuming of radioactive dust needs to be performed around the vicinity of an accelerator. Themagnet coils of the accelerator were recently repaired and some grinding of welds were necessary,resulting in radioactive dust to be cleaned up. The area where the vacuuming is needed is correctlyposted as an airborne-radioactivity area, a high-radiation area, and a contamination area. Severaloptions exist regarding the radiological aspects of performing the vacuuming work. The healthphysics supervisor is examining several options before writing up the RWP.

Specific information about the work area is listed below:• Primary contaminant is manganese-54 (Mn-54) oxide.• Ambient dose equivalent rate is 10 rem/hr.• Job will take approximately 1.5 hours to perform.• Measured airborne concentration is five times the DAC.• A movable shield with arm ports could be used between the worker and the bulk of the dust to

be picked up. This shield attenuates the dose equivalent rate to 1 rem/hr, but will increase theestimated job duration time to two hours.

• Respiratory protection with a protection factor (PF) of 50 is available, but will increase theestimated job duration time to three hours.

The health physics supervisor is examining the following options. All options assume that protectiveclothing will be worn during the job.

1. Use one worker, no shield, and no respiratory protection.2. Use one worker, the shield, and no respiratory protection.3. Use one worker, the shield, and respiratory protection.

Estimate the total dose equivalent to the worker under for each option, and identify the option withlowest total dose equivalent.

Your Solution:

Exercise 4



What are some other options that the health physics supervisor might consider?

Your Solution:

Exercise 5

Identify a sensitive issue that the health physics supervisor can expect to arise when instructing theworkers about the performance of this particular task.

Your Solution:



Exercise Solutions

Exercise 1, Solution(Any reasonable paraphrase of the following is acceptable.)

The RWP will list the radiation controls, requirements, and restrictions for the work. The followingare some elements relevant to this job:

• Since the area is a contamination area, protective clothing is necessary and must be worn. Theclothing should probably consist of coveralls, gloves, shoe covers, and hood.

• The worker should wear at least a whole body dosimeter and pocket dosimeter.• The worker should minimize the time near the most contaminated areas.• The worker should be instructed not to go into the high-radiation area to pick up debris.• The worker should be instructed to pick up as much as possible in the 30-minute time frame, and

then exit the area.• A supervisor should be outside the area to monitor the worker's time spent in the area, answer

questions from the worker, and supervise the work.

A quick estimate of the dose equivalent to the worker would be:

(10 mrem/hr) (0.5 hr) = 5 mrem

Exercise 2, Solution(Any reasonable paraphrase of the following is acceptable.)

The debriefing should include the following items:• Was the objective of the RWP met? Was the debris picked up and placed in the radioactive waste

cans? Was the task completed, or was there more debris remaining that could not be picked upin the allowed time frame?

• Did the worker stay out of the high-radiation area in the corner?• Did the worker encounter any unanticipated problems that were not addressed in the RWP?• Was the protective clothing appropriate for the situation (i.e., did it fail; would another type of

clothing, or glove, etc., have worked better for the job to be performed)? Was it safe for theemployee considering factors such as heat, humidity, lighting, water, etc.? Did it preventcontamination of the employee?

• Did the worker avoid the areas with the highest contamination?• Were the pocket ionization chamber results within the limit set for the job? If not, what factor(s)

contributed to additional exposure?• What can be improved when other similar jobs have to be performed?It appears that the job was performed according to plan with these exceptions: The worker had to



spend more time than necessary near the areas of highest contamination since the radioactive wastecontainers were located there, and the worker's estimated dose equivalent for the job was greater thananticipated, perhaps for the same reason. As far as the worker's performance, he did notice theproximity of the waste containers to the contaminated spots, but did not question this. He could havemoved the containers to a different location in the area, or asked the supervisor who, was outsidethe area, about what to do in this situation. This may have contributed to the higher-than-estimateddose equivalent that the worker received. For future jobs, the workers could be instructed to movethe containers to an area away from areas of highest contamination.

Exercise 3, Solution

Option 1: No shield, no respiratory protectionExternal exposure: (10 rem/hr) (1.5 hr) = 15 remInternal exposure: (5 DAC) (1.5 hr) = 7.5 DAC-hours

(7.5/2000 DAC-hrs) (5 rem) = 0.01875 rem or about 19 mremTotal dose equivalent: 15 rem + 19 mrem = 15.019 rem

Option 2: Use shield, but no respiratory protectionExternal exposure: (1 rem/hr) (2 hr) = 2 remInternal exposure: (5 DAC) (2 hr) = 10 DAC-hours

(10/2000 DAC-hrs) (5 rem) = 0.025 rem or 25 mremTotal dose equivalent: 2 rem + 25 mrem = 2.025 rem

Option 3: Use shield, use respiratory protectionExternal exposure: (1 rem/hr) (3 hr) = 3 remInternal exposure: (5 DAC/50 PF) (3 hrs) = 3 DAC-hours

(0.3/2000) (5 rem) = 0.75 mremTotal dose equivalent: 3 rem + 0.75 mrem = 3.00075 rem or 3 rem

Clearly, Option 2 results in the lowest total dose equivalent. All other factors being equal, this wouldbe the best option.


The health physics supervisor might consider using several people in short shift to perform the task.The advantage here is that the dose would be distributed among several individuals. This optionwould be especially attractive in meeting site-specific administrative controls.




A sensitive issue that will arise on the part of the workers is why respiratory protection is not neededin an airborne activity area. The health physics supervisor must be very careful to explain the primarilyexternal hazard associated with this particular radionuclide, even though dust containing theradionuclide is present. Also, the health physics supervisor must be sure to explain that the total riskto the individual is the result of BOTH internal and external exposure. This will be easier for theworkers to accept if they have been properly trained to begin with, and if they are not hearing thisconcept for the very first time.



4. SUGGESTED ADDITIONAL READINGS AND/OR COURSES

Readings

• 10 CFR 835, Occupational Radiation Protection.• DOE N 441.1, Radiological Protection for DOE Activities.• DOE/EH-0256T (Revision 1), Radiological Control Manual.

NOTE: See Appendix 3A, Checklist for Reducing Occupational Radiation Exposure,pp. 3-35 & 3-36.

• DOE Order 5480.4, Environmental Protection, Safety, and Health Protection Standards• G-10 CFR 835, Revision 1, Implementation Guides for Use with Title 10 Code of Federal

Regulations 835.• International Commission on Radiological Protection. Cost-Benefit Analysis in the Optimization

of Radiation Protection (ICRP 37). New York: Author.• International Commission on Radiological Protection. Recommendations on the International

Commission of Radiological Protection (ICRP 60). New York: Author.• Pacific Northwest Laboratory. (1988). Department of Energy Health Physics Manual of Good

Practices for Reducing Radiation Exposure to Levels that are As Low As Reasonably Achievable(ALARA) (PNL-6577). Richland, WA: Author.Beir V Report, Health Effects of Exposure to Low Levels of Ionizing Radiation, 1990.

Courses

• DOE/EH-0450 (Revision 0), Radiological Assessors Training (for Auditors and Inspectors) -Fundamental Radiological Control, sponsored by the Office of Defense Programs, DOE.

• Applied Health Physics -- Oak Ridge Institute for Science and Education.• Health Physics for the Industrial Hygienist -- Oak Ridge Institute for Science and Education.• Safe Use of Radionuclides -- Oak Ridge Institute for Science and Education.• Radiation Protection Functional Area Qualification Standard -- GTS Duratek.

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